As described in Patent Literature 1 for example, there has been conventionally proposed a semiconductor acceleration sensor including a movable electrode formed in a weight, a fixed electrode opposed to the movable electrode, a first beam connected to the weight and movable in accordance with acceleration, a first stopper regulating a displacement amount of the first beam, and a second beam supporting the first stopper. The first beam includes multiple beam portions having different spring constants. A displacement amount of each beam portion is regulated by a corresponding stopper. A stopper and an adjacent beam portion are connected. The movable electrode and the fixed electrode form a capacitor. This structure reduces degradation of a capacitance linearity of the capacitor when the application of acceleration largely displaces the movable electrode.